Vascular Ultrasound: Current state, current needs, future directions

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1 Vascular Ultrasound: Current state, current needs, future directions Laurence Needleman, MD Thomas Jefferson University Hospitals Sidney Kimmel Medical College of Thomas Jefferson University

2 Disclosures Member, Intersocietal Accreditation Commission Vascular Testing (unpaid)

3 Overview What tests are done for vascular disease? What is the natural history of vascular disease using ultrasound? What shortcomings exist for US vascular diagnosis? What is the future direction of ultrasound? of vascular ultrasound?

4 Gray scale ultrasound Carotid stent

5 Graphical representation of Doppler Makeup Doppler frequency or velocity - y axis Time - x axis Strength of signal - gray scale Number of reflectors Spectral Doppler

6 Color Doppler Carotid stenosis

7 Color Doppler Artifacts

8 Vein of Galen Aneurysm

9 Inferior Mesenteric Artery

10 Current state

11 Tests Venous ultrasound obstruction DVT Carotid duplex ultrasound - stenosis Aortic ultrasound - aneurysm Abdominal Doppler Renal arteries - stenosis Liver (portal hypertension) hypertension, flow direction Ovaries and testes increased or decreaed flow, tumors

12 Acting Surgeon General Issues Ca ll to Action to Prevent Deep Vein Th rom b os is a n d Pu lm on a ry Em b olis m FOR IMMEDIATE RELEASE Monday September 15, 2008 Contact: Office of Public Health and Science (202) Acting Surgeon General Steven K. Galson, M.D., M.P.H., today issued a Ca ll to Action to reduce the number of cases of deep vein thrombosis and pulmonary embolism in the United States. Galson urged all Americans to learn about and prevent these treatable conditions. Deep vein thrombosis and pulmonary embolism affect an estimated 350,000 to 600,000 Americans each year, and the numbers are expected to increase as the U.S. population ages. Together, deep vein thrombosis and pulmonary embolism contribute to at least 100,000 deaths each

13 Venous thromboembolic disease Ultrasound is the gold standard to diagnose deep venous thrombosis in the legs CT and NM are the major tests to diagnose its major complication, pulmonary embolism DVT and PE are associated with mortality, diagnosis of cancer, and chronic diseases

14 Venous US Normal Compression A A Vein

15 Noncompressible Vein: Causes Acute venous thrombosis (DVT) Scarring Inadequate compression Noncompressible Deep venous thrombosis Without compression With compression Acute Deep Venous Thrombus

16 Acute Venous Thrombosis Soft, deformable with compression Enlarges vein Smooth Free floating CFV Great saphenous vein Femoral vein

17 Initial -8mm +7 mos 4mm +11 mos 4mm +13 mos 9mm Popliteal vein recurrent thrombosis +45 mos 4mm

18 Virchow s Triad

19 Development of DVT depends on baseline risk and risk events Normal Thrombophilia

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21 Duplex Doppler ultrasound is used to diagnose and grade stenoses Gray scale narrowing Color narrowing and color changes of elevated velocity Spectral Doppler in and beyond stenosis

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23 Bournoulli and Stenosis Pre-stenosis Stenosis Post-stenosis Total energy = Kinetic + potential Potential energy very decreased Total energy lower Potential energy decreased Kinetic energy very increased

24 Increased Velocity in Stenosis

25 Pre and In the stenosis

26 Beyond the stenosis Change from small lumen to large lumen destabilizes flow Jet spreads out High velocity also destabilizing Frank breakdown of regular flow disturbed flow (and evenually turbulence)

27 Post Stenotic Disturbed Flow

28 Criteria for Stenoses Some circulations use absolute velocity Internal carotid artery Most circulations do not have standard velocities - Need ratios Some circulations use downstream effects in addition Peak systolic velocity ratio (velocity ratio) Highest velocity in stenosis divided by velocity proximal to stenosis (in normal vessel) IC:CC ratio PSV ratio in arteries Renal aortic ratio Intrarenal criteria

29 Abdominal aortic aneursym Abnormal dilatation of aorta If enlarges over 5 cm and is untreated, rupture may occur High mortality if rupture Approved for Medicare screening

30 Abdominal Aortic Aneurysm (AAA)

31 AAA gray scale ultrasound

32 AAA- Easy to measure, hard to acquire

33 Endoleaks

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35 Natural history of atherosclerosis Preclinical disease Flow mediated dilatation, intima media thickness Location of plaque Clinical disease Degree of stenosis Plaque characterization Prediction of disease

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37 Drawing of cross-sections of identical, most proximal part of six left anterior descending coronary arteries. Stary H C et al. Circulation. 1995;92: Copyright American Heart Association, Inc. All rights reserved.

38 Intima Media Thickness Used in epidemiological studies Strong predictor of future cardiovascular events Additive to some traditional cardiovascular risk factors Used in pharmaceutical studies How can it be applied to the individual? Reproducible clinically? How does it compare to other tests?e.g. history, lipids, CRP, CT coronary calcium scoring? One time or serial test?

39 O Leary et al NEJM 1999:340:14-22

40 Weird Doppler from the bulb

41 Flow separation

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44 Plaque

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54 This plaque is different

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56 Current needs and problems

57 Calcifications and depth

58 PICA

59 PICA color

60 Before calcification

61 In

62 Distal 79 cm/s

63 Additional scanning

64 PSV 159, EDV 20, IC:CC 2

65 Duplex DSA Correlation Duplex Success Dark green best Light green Yellow Red worst Eiberg Eur J Endovasc Surg

66 Duplex Arteriography 1020 scans Not well visualized Iliac 73 Femoral 26 Popliteal 17 Infrapopliteal 221 Arterial wall calcifications 64 Poor runoff 18 Hingorani AP et al. Vascular 2008;16(3)

67 Solutions Better sonographers to find best direction CTA Future Multiplanar ultrasound Volume acquisition Volume flow (?) Sensitive techniques to low flow

68 Angle

69 Velocity requires angle correction

70 60 o Angle Correction 60 o 92.6cm/s 60 o 60 o 83.2cm/s 69.1cm/s

71 Angle errors worse for higher angles Table courtesy of Frank Miele

72 Angle Correction 60 o 92.6cm/s 50 o 90.9cm/s 70 o 122cm/s 88 o 4cm/s

73 What is angle?

74 Solutions Angle dependent scanning Multidirectional acquisition Less reliance on Doppler Gray scale modes

75 Is carotid ultrasound a public health problem? Same results in different laboratories give different degrees of stenosis

76 SRU Carotid Consensus Grant EG, et al. Radiology 2003;229:340.

77 World Federation Neurology

78 2002 ICAVL Survey 100 Vascular Labs 11 Different Criteria Unpublished data courtesy Ms. Sandra Katanick, Intersocietal Accreditation Commission

79 2010 ICAVL Survey 152 Vascular Labs; >16 Diagnostic Criteria

80 Future directions

81 Trifurcation of Ultrasound Point of care Traditional Ultrasound Personalized ultrasound (Specialized care) ER, primary care, some specialists Radiologists, some specialists Ultrasound specialist and team Problem centered, short duration Performed by doctor Protocol driven, more complete, Variable duration Performed by sonographer/vascular technologist, presented to doctor Detailed diagnostic or therapeutic scans, time depends on study but generally long (e.g. biopsy, contrast injection, therapy) Performed by doctor, usually with assistance (nurse, technologist)

82 Trifurcation of Ultrasound Future trends Point of care Traditional Ultrasound Personalized ultrasound Prettier pictures Few or no buttons Wireless acquisition and storage Simpler controls Volumetric acquisition Post processing Less dependency on sonographer skill (e.g. smart Doppler, protocols, angle independence, automatic measurements) Flow and pressure Contrast approval by FDA Drug delivery New modes with better macro and micro vasculature